Process of and apparatus for drying materials



uc ZU, H. BUEL PROCESS OF AND APPARATUS FOR DRYING MATERIALS Filed April18, 1921 5441mm tor V HILLHUUSE EL/EL Y Patented Oct. 20, 192 5.

. HILLHOUSE BUEL, OF SEATTLE, WASHINGTON.

raoonss or AND nrrnniirusron. DRYING mnrrmmns. Y

Application flle'd April 18, 1921. Serial 110,462,439.

I To all whom it'may concern; i

Be it known that I, HILLHOUSE BUEL, a citizen of the United States,residing'in the borough of Manhattan, city, county, and State of NewYork, har e invented certain. new and useful, Improvements in Processesof and Apparatus for Drying-Materials, of which the following is a full,clear, and complete description.

My invention relates the art ofv extract-.

ing moisture from materials and has as its principal object theprovision of a process whereby moisture may be removed frogn materialseconomically and at a high rate of speed. A second object of myinvention is to provide a process whereby materials may be comminuted ina rapid and economical manner with a minimum damage to the granular orthe fibrous structure. A further object of my invention is to provide aprocess whereby materials may be dried at a maximum rate of speedwithout injury to the material. A further object of my invention is toprovide a drying apparatus adapted for use in accordance wlth myprocess, and which will be convenient and efficient in operation. v

The novel features of' my invention are pointed out. with. particularityin the appended claims. The invention itself, however, with furtherobjects and advantages,

will best be'understood from the following description taken inconnection with the accompanying drawing in which Fig. 1 is a verticalcentral section of a moisture extractor according to my invention.

Fig. 2 is an elevation of a liquid separator preferably used inconnection with the apparatus shown in Fig. 1.

-Fig. 3 is a diagrammatic elevational view of the condenser used inconnection with the I apparatus illustrated in Fig. 1.

Fig. 4 is a detail view illustrating the heating elements of theextractor shown in F ig. 1.;

In the drawing, 1 is a vacuum chamber having an outer heat insulatingcovering 2 and a lining 3 adapted to serve not only as an additionalmeans for preventing the es-' cape of heat from the interior of thechamber 1, but more particularly for preventing harmful reaction betweenthe metal wall of -most point in their rotation. livered to the conduit6 from a hopper 8' chamber 13 and is surrounded the chamber and thematerial being treated,

as well as to protect the metal wall from the temperature within chamber1.

Material is supplied direct] pockets 5 therein, in which the materiallodges as the pockets pass through the lower portion of conduit'6. Thedrum 4 rotates within a block 7 and the surface of the drum,

with the exception of the pockets 5, makes a working fit with. saidblock whereby excluded,-but material which'lodges 1n pockets-7 isconveyed out of the I dropped into'the central upper portion of p to thechama ber by a rotating-feeding rum 4" having air is conduit 6- andchamber 1 as the pockets pass by the lower- Material is deinto which-itis fedby'feed pipe 9. pre

fer. to providean agitator 10 in the hopper 8 and a conveyoror feed worm11 in the conconveniently mounted-on a common shaft 12. The majorportion of conduit 6 is preferably enclosed within --a heat insulateding coil 14 or other means for maintaining the temperature. within theconduit 6110- initially heat the material.

In case the materials solids mixed with excess of liquid, I remove theexcess of liquid-by passing the materials over a screen or by means foreifecting such separation being i1- lu'strated in Fig. 2, in ,which 15indicates a chamber'contalning an inclined screen 16. Material mixedwith water is introduced into the chamber 15 through pipe 17, the

to be dried comprise other suitable means, a

duit 6, agitator 10 and worm 11 both being -7 by the heatsolid matterpassing down stream 16 under" the influence of pipe 9 by whic itisconducted to the feed hopper 8 of the apparatus previously described.The liquid passing through screen 16 is drained out of chamber15 throughpipe 18, and runs to waste.

Within the chamber 1 I arrangeheated elements 19 and 20. Elements 19 and20 are preferably arranged near thewall of the chamber 1, and arecovered on their outer sides by heat insulation 21, their inner sidesradiating heat toward ,the centre of'the chamber. Preferably,,moreover,the inner surfaces of these elements are so arranged as (Donate a zoneof intense radiant heat at gravity and out through the diant energy;in,-a. circular line whose plane will be understood, however, that thelines is above drum",4, ithe major portion of the rays of energy fromopposite sides of the element 19 crossing immediately below drum 4, asindicated by the lines 22 in Fig. 1. It

22 and 24 represent only diagrammatically a portion of the energy rays,and that other rays radiate in various directions from the heat sourcesin the element 19 and that while the zone ofinost intense heat will beas illustrated at the intersection of the diagrammatic lines 22 and 24,the entire interioror-bowl' of the radiant elements will be at a highheat. The circle on which element 19 tends to focus is indicated on Fig.

1 by the points 23, 23. Not all the rays of energy will, however, focusexactly at these points. The element 20 is arranged, as illustrated, tohave a cylindrical inner face projecting its rays of radiant heathorizontally in a zone lying immediately below the block 7, as indicatedby the lines 24. Where therays 22 cross rays 24 immediately below drum4- is of course the point of most intense heat.' I may increasefocusing, as shown, in order that the mate-- rial dropping from thepockets 5 and drum 4 may be acted on somewhat longer by the theintensity of the radiant-heat or energy immediately below drum'4 byforming the element20 so as to focus atth'is point, but I prefer thatelement 20 should be nonradiant heat. The elements 1 9 and 20 aresupported from the wall of chamber 1 by suitable brackets, such as 25. Iprefer to make these heaters or radiators 19 and 20 of the electric typewherever cheap electric power is available as in regions adjacentydro-electric developments, but where electric power is expensive, it ismore economical to use other methods of heating the radiators and haveillustrated insulating bushings 26 extending throughthewall of chamher 1through which electric conductors" 27 may be connected with the heaters.In the apparatus illustrated in Fig. II have arranged the resistancemembers ofelements19- and 20 in series so that only two bushings 26 arenecessary. However I do not limit myself-to this. The elements 19 and 20preferably are made of insulating material of somewhat refractorycharacter, such as-fire clay and the resistance members are arranged inthe refractory material in a well known manner, as indicated at 28, Fig.4, the resistance wires being insulated-from the radiating body by alayer 28 of mica or like material. However, I do not limit'myself to anyparticular design of radiator.

The upper portion of chamber 1 connects with vapor conduits 29, 29,which are combined and connected toa pipe 30 (Fig. 3)-

removed. As the radiant energy is intense inthe zone immediately belowthe inlet drum 4, the moisture in the material bursts into steam, and ifthe material is not comminuted, the steam causes such comminution, atthe same time that drying occurs. For instance, by myprocess andapparatus, I can produce a dried wood pulp with maximum economy byfeeding moist partially digested chips to my apparatus. Due to theaction are completely separated, but are of maximum length and strength.

The temperatureof radiating elements 19 and 20 is preferably as high asthe resistance material will stand, as the higher the temperature themore rapid the drying action. The practical operating temperature limitwhen using nicrome wire as resistance materialis about 1800 F. Otherresistance elements, olferi'ng a wide range oftemperatures may, however,be employed. Evidently, however, the higher the temperature of theheater or radiator, the morev rapidly a given material can be passedthrough the apparatus.

time it falls to the bottom ofthe vacuum chamber: The temperature of thematerial treated is kept down while in the zone of concentratedradiation by the evaporation and expansion of moisture therefrom and itof the steam, as described above, the fibres The material is dried bythe is removed from the vacuum chamber assoon as or almost as soon asdry. The point of outlet for the material being only slight ly exposedtothe radiant energy, the material can receive no damage while in the actof being removed from the chamber. -Moreover the sensibletemperature ofthe portions I be substantially a duplicate of the drum 4. r

The material may then be baled or otherwise prepared for shipment bymeans of a press 34: or other suitable apparatus. Preferably,

the discharge drum 33 delivers the comminuted and dried materialdirectly to the compressing or packing apparatus illustrated in Fig. 1.The chamber and outlet pipes 29 must be of ample size so that watervapor will pass to the condenser without evidently reducing the vacuumin chamber 1. Moreover I do not wish the active surfaces of radiators 19and 20 ever to fallbelow a red heat as then the vapor escaping from thematerial will slow down the transference of radiant energy to thematerial to such an extent that the material is not -sutlicientlydriedin the zone of concentrated energy. In order to cause comminution ofmost organic solids the surfaces of these radiators must be at a brightred heat. I

It will be seen that I havedevised a process and apparatuswhereby'materials may be dried rapidly with high economy of heat, andwithout damage to materials, even of a delicate character. I alsoaccomplish comminution of the materials treated at the same time theyare dried, provided their character makes it possible and desirable'todo so.

It will be understood that where I have used the word comminute orcomminuted in the foregoing description and appended claims, I intend toinclude the idea of shredding. p

I anticipate using my invention in drying pulp, milk, cotton forspinning, cotton and otherfibrousv material, minerals, and otherinorganic and organic substances, as well as simultaneously comminutingand drying woodchips and other materials.

While I have disclosed the preferred. man ner of practicing myinvention, and illustrated and described the preferred apparatusaccording to my invention, I do not wish to be limited to details ofdescription or illustration. 1

Having thus described my invention, 1

' claim 1. The method of comminuting moisture bearing materialscomprising suddenly converting the. moisture in the materials to steamby'exposing the materials to intenseradiant energy in vacuo.

2. The method of removing moisture from materials in a vacuum chambercomprising exposing the materials to radiant heat while unsupported insaid chamber.

3. An apparatus for drying materials comprisipg in combination a chambermeans for maintaining a part1al vacuum 1n sald chamber, means forintroducing and removing materials from said chamber, and means forcreating a zone of radiant heat through which said materials pass withinsaid chamber.

4. An apparatusfo'r removing moisture from materials comprising incombination a chamber, means for maintaining a vacuum in said chamber,means for introducing ma- 'terial into said chamber, means for creatheatwithin said'chamber arranged to confcentrate the heat energy radiatedthereby within a restricted field.

6. An apparatus for removing moisture from materials comprising incombination means for heating the material to be dried, a'chamber, meansfor introducing said material. into said chamber while in a heatedcondition, means for maintaining a partial vacuum in said chamber, andmeans for subjecting said material to radiant hea within said chamber.

. 7. In combination with a vacuum chamber, means for preheating andcompressing moisture bearing materials before delivery to chamber, meansfor continuously injecting-moisture bearing material into the chamber,means to deliver radiant heat onto the material on its injection intothe chamber,

and means to discharge the dried and com;-

material with concurrentdehydration thereof, means for continuouslyinjecting moisture bearing material into the chamber, and means todischarge the dried and comminuted material from said chamber incontinuous, automatic operation without breaking the vacuum. 1 v

9. The combination with a vacuum chamber or pan, heating means insaidchamber for causing interstitial explosion of the moisture in andthe minute separation of the fibres and particles of the moisture 5bearing material with concurrent dehydrationthereof, a means formaintaining a partial'vacuum in the chamber, means for continuouslyinjecting moisture bearing material into the chamber, means fordischarging the dried and comminuted material in continuous automaticoperation from the chamber without breaking the vacuum.

10. In combination with a vacuum chamber, heating means in said chamberfor causing interstitial explosion of the moisture in and the minuteseparation of the fibres and particles of the moisture bearing materialwith concurrent dehydration thereof, means for preheating andcompressing moisture bearing materials before delivery to chamber, meansfor continuously injecting moisture bearing material into the chamber,and means to discharge the dried and comminuted material from saidchamber in continuous, automatic operation without breaking the vacuum.

11. The combination with a vacuum chamher or pan, a means formaintaining a par tial vacuum in the chamber, means-for preheating andcompressing moisture bearing materials before delivery to chamber, meansfor continuously injecting moisture bearing material into the chamber,means to deliver radiant heat onto the material on its injection intothe chamber until the material is dried and comminuted, means fordischarging the dried and comminuted material in continuous automaticoperation from the chamber without breaking the vacuum.

12. The combination of a vacuum chamber, means for maintaining a vacuumin the chamber, means for instant and continuous injection of materialinto the chamber without breaking the vacuum, a white hot source ofradiant heat for simultaneously and almost instantly drying andcomminuting the material, and means for discharging dried and comminutedmaterials from the chamber.

13. The combination of a vacuum chamber, means for preheating andcompressing moisture bearing materials before delivery to said chamber,means for maintaining avacuum in the chamber, means for instant andcontinuous injection of said materials into said chamber withoutbreaking the vacuum, a source of radiant heat for simultaneously andalmost instantly drying and comminuting thematerial, and means fordischarging driedand comminuted materials from the chamber.

14. In an apparatus of the class described, the combination of a vacuumchamber, a radiator in said chamber, means for maintaining said radiatorat a temperature of at least a red heat, and means whereby material tobe treated may be introduced into and removed from a zone of energyradiated from said radiator and within said chamber.

15. The process of drying and comminuting moisture containing materialsconsisting in heating said materials under atmospheric pressure and thensubjecting them to the simultaneous action of radlant heat and vacuum.

16. The process of drying material consisting in introducing thematerial into a field or zone of intense radiant energy in not come in'contact with vacuo and removing said materials from said zone as soon asthey are substantially dried. 4,

17. The process of simultaneously drying and comminuting moisturecontaining materials comprising comminuting the' material by the rapidvaporizationof the contained moisture in vacuo under the influence ofintense radiant energy, and substantially removing the material'from theinfluence of said radiant energy as soon as the material issubstantially dry.

18. The process of drying material comprising passing them in vacuothrough a zone of radiant energy of an intensity to vaporizesubstantially all the moisture during the passage of the materialthrough said zone.- c

19. The process of drying materials comprising dropping them in vacuothrough a zone of radiant energy of such dimensions and intensity thatthe material is substantially dried during its passage through said.zone.

20. The process of-simultaneously drying and comminuting moisturecontaining materials comprising dropping them, in vacuo, through a zoneof radiant energy and comminuting and substantially drying saidsubstances b the vaporization of moisture 95 while falling through saidzone.

21. The process of simultaneously comminuting and drying moisturebearing substances comprising heating the substance,

injecting said substance into a zone of racontained moisture whilefalling through said zone.

22. The combination of a vacuum chamber, means to introduce moisturecontaining materials into \said chamber, a luminous radiator in saidchamber to whose radiation the material is exposed, and means forremoving dried material from said chamber.

23. The -method of removing moisture from materials comprising exposingthe material.simultaneously to vacuum and to direct radiant heat fromradiating means having at least one portion at a temperature as great asthat of thedark blood red and under conditions'such that the materialdoes the surface of said radiating means.

24. A drying apparatus comprising in combination a chamber, means formaintaining a partial vacuum in said chamber,

means for supplying heat within said cham- 5- 1 means to while in thechamber, means to prevent the material from contact with said heatdeliv-' er1 ng means, and means to discharge the drle'd and comminutedmaterial from said chamber in continuous automatic operation withoutbreaking the vacuum, said heat del verlng means comprising a surface aport1on of which has at least a dark blood red temperature.

' HILLHOUSE BUEL.

